Dairy and the Environment

The Environmental Impacts of Dairy

The production of animal products, including dairy, has become increasingly industrialized and consolidated. The second half of the 20th century saw increasing expansion, industrialization, and corporate concentration in the meat, egg, and dairy industries in Canada and the United States in particular. Many small, family-run farms unable to compete with the large agribusiness companies have been pushed out of business. There is a perception that these larger companies have triumphed because they are more efficient; they can appear efficient because many of their costs—environmental impacts chief among them—are externalized (see Fitzgerald 2015).

The environmental impacts of dairy production are many, and they are increasingly receiving the attention of researchers, the general public, and the industry. Illustrative of the latter, the Dairy Farmers of Canada recently announced in their 2019-2020 annual report that they are undertaking an extensive marketing campaign focused on environmental sustainability. They write, “environmental sustainability is front and centre with our consumers and is something inhere to dairy farmers! The ongoing development of the proAction environment module will help better support providing that story to consumers” (p. 35)

The following information is intended to provide the average member of the general public with the information they need to properly contextualize this ‘story.’ Marketing is indeed powerful, but the antidote can be found in knowledge, which is essential for making informed decisions.

Four main significant environmental impacts are examined in turn here: land use, deforestation, and the impact on biodiversity; water use and degradation; compromised air quality; and contribution to global climate change. Although each impact is examined separately, it is important to keep in mind that the environmental impacts of dairy production are often interconnected.

Land Use, Deforestation, and Biodiversity Loss

Dairy production is land-use intensive, not necessarily in terms of housing the animals that the milk is derived from—they are often concentrated together in confined spaces because doing so is more profitable than allowing the animals to graze on pastures. A great deal of land is needed, however, to produce feed for the animals to consume. And the conversion of land for feed production often contributes to deforestation. This is one reason why the Food and Agriculture Organization of the United Nations (2013: 1) describes the livestock sector in general as ‘resource-hungry’; that is, the industrialized production of animals for dairy and meat is less efficient than producing crops for human consumption directly.

The loss of natural habitats via deforestation, by extension, contributes to biodiversity loss. The 2019 report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) provides grim statistics that paint a picture of the crisis at hand: the biomass of wild animals globally has declined by 82% and approximately 25% of species are now under threat of extinction.  

Deforestation is not the only way that the dairy industry threatens biodiversity. The land that is converted to feed production attracts rodents, particularly because the crops grown are nutritious. Luque-Larena, Mougeot, Arroyo, & Lambin (2018) identify alfalfa as being particularly attractive for rodents. In their cleverly titled academic article, “‘Got rats?’ Global environmental costs of thirst for milk include acute biodiversity impacts linked to dairy feed production,” they write “wherever alfalfa is grown, rodent populations periodically attain outbreak densities, when acute crop damages and zoonotic disease transmission cause substantial economic and public health impacts” (2752).

When rodent populations climb, the response is often to achieve control by using rodenticides (‘rat poison’). Luque-Larena and colleagues (2018) cite a projected 38% increase in demand for rodenticides between 2015 and 2021. These poisons may be intended to kill rodents, but their impact extends far beyond. The researchers explain that these poisons also cause the indirect deaths of other species, such as raptors, which consume poisoned rodents. They therefore conclude that “stricter global regulations on the use of rodenticides are needed to minimize environmental burdens wherever dairy feed is grown to quench the thirst for milk” (p. 2752).

A few additional words about zoonoses (i.e., illnesses that breach the species barrier) are warranted here. In addition to the risks of zoonotic illness transmission posed by outbreak rodent populations described by Luque-Larena and colleagues, the dairy industry—like the industrial animal agriculture sector more generally—is linked to zoonotic illness transmission in a couple other ways. First, working in close proximity with animals inherently increases the risk of zoonotic illness transmission. In January, 2021, for instance, researchers in the Netherlands were busy investigating a suspected zoonotic illness that had originated on goat farms (goats are kept for both milk and meat). They have connected it with a 20-55% greater risk of developing pneumonia among those within a 1.5km radius of a goat farm (Kevany, 2021). Second, because it contributes to deforestation, dairy production also facilitates closer contact between wildlife and people, which can contribute to zoonotic spillover (see Beirne 2020). As the COVID-19 pandemic has demonstrated, zoonotic illnesses can harm both humans and other animal species.

Water Use and Pollution

There are two main impacts of dairy production on water: water use and water degradation. Just as the use of land to produce meat and dairy for human consumption is less efficient than using the land directly to produce crops for human consumption, the same can be true of the use of water. Researchers who have conducted analyses of the water footprint of animal products conclude “The water footprint of any animal product is larger than the water footprint of crop products with equivalent nutritional value…  it is more water-efficient to obtain calories, protein and fat through crop products than animal products” (Mekonnen and Hoekstra 2012: 401). As with land use, most of the water use comes from the production of animal feed.

In their analysis of the water footprint of several types of animal products across several countries, Mekonnen and Hoeskstra (2012) provide a useful disaggregation that makes it possible to isolate the specific impact of dairy. They categorize water impact into three types: surface and ground water consumed, rain water consumed, and the amount of water needed to assimilate the pollutants produced. They further disaggregate by specific dairy product and mode of production. The adjacent table provides a summary of their findings.

An interesting difference is observed between grazing and industrial modes of production: whereas the water use for other animal derived products is noticeably higher in the industrial mode of production than the grazing mode, that is not the case with dairy production. In most of the categories above, the use in grazing is higher than industrial. Overall, dairy cattle have the second largest share of the livestock water footprint globally (19%), second only to cattle used for beef (their share is 33%). Moreover, while the total average water footprint of milk is 1020, it is only 322 for vegetables (Mekonnen and Hoekstra, 2012).

In addition to water use, the dairy industry’s impact on water includes water pollution, and one of the key vehicles for this pollution is manure. Two thousand cows will produce approximately 250,000 lbs of manure daily (FoodPrint, n.d.). Even smaller animals used for dairy produce a lot of manure. For instance, a conservative estimate of the manure output of a herd of 2,000 goats is 12,000 lbs daily (Fitzgerald, Wilson, Bruce, Wurdemann-Stam, & Neufeld, 2021).

Storage in manure lagoons and spreading on fields as a form of fertilizer are the two main methods of manure use/disposal used in the industry. Both methods come with associated limitations. Manure lagoons have been known to leak and to be breached by severe weather events, and manure spread on fields can leach into groundwater (see Fitzgerald 2015). The problem is that manure contains elements that can be hazardous to the environment and human health. Manure is high in phosphorus and nitrogen. These nutrients can cause eutrophication of waterbodies if they appear in large enough concentrations (West, Liggit, Clemens, & Francoeur, 2011; Centner, 2006). Simply put, eutrophication can result in massive fish kills because the overproduction of plants results in less available oxygen. A study of dairy production around the Great Lakes identified potential eutrophication as the largest relative impact on the environment (Kima et al., 2019).

Eutrophication can also be caused by runoff of synthetic fertilizers applied to crops to produce feed for animals. Kima and colleagues (2019) conclude their study of two dairy farms around the Great Lakes (one relatively large, and the other small) by stating “Our findings point to crop production as a major contributor to potential human toxicity and aquatic ecotoxicity for both dairy farms. Primarily, soil and water affected by manure, fertilizer and pesticide applications trigger the increased impacts” (p. 9).

Manure can also contain pathogens that, while harmless to the animals that harbour them, can be deadly for humans. For instance, approximately 20 years ago, Walkteron, Ontario experienced an outbreak of E.coli 0157:H7 in its drinking water. Seven people were killed and 2,300 others experienced attributable illness. The E.coli (as well as Campylobacter jejuni) that impacted the drinking water originated in manure that was spread on a field, within the legal application limits, and was taken by significant rain runoff into a well that supplied the town with its drinking water (Salvadori, Sontrop, Gard, Moist, Suri, and Clark, 2009).

Photo gallery above shows satellite and aerial photos of algae blooms as a result of eutrophication.

Air Pollution

Dairy production also contributes to air pollution, both proximate to farms and more broadly in the form of greenhouse gas emissions, discussed in the next section.

Research on industrial animal agriculture in general has documented increased risk of respiratory illnesses among workers in the industry due to compromised air quality. There has been considerably less research focused on dairies, but the research that has been conducted has documented significant workplace risks in that sector as well. One group of researchers summarizes the risks as follows:

the dairy industry has long been recognized as a high-risk occupation, characterized by elevated rates of injury, illness, and turnover. In fact, it is one of the few industries that experienced an increase in non-fatal injuries between 2010 and 2011. Some of the more common occupational hazards include risks associated with machinery operation and repair, large animal handling, respiratory exposures, ergonomic risks including repetitive motions and high muscle forces required in parlor milking, and fatigue due to long hours and physical demands (Menger, Pezzutti, Tellechea, Stallones, Rosecrance, and Roman-Muniz, 2016: 2).

The ‘respiratory exposures’ include ammonia and hydrogen sulfide, which are found in manure and cause irritation, and at high concentrations can even cause death. There is also a significant amount of airborne particulates on dairy farms – including those from dried manure, dust, and feed – that can negatively impact respiration (FoodPrint, n.d.).

Researchers in California (Eastman et al., 2013) quantified the respiratory impact by examining the respiratory capabilities of workers and comparing them with a control group. They found compromised airflow and diminished vital lung capacity among workers, controlling for smoking and the time of their work shift, which were significantly greater than the control group. Based on their findings – and those of other studies that have documented higher rates of chronic bronchitis, wheeze, allergies, pneumonitis, and organic dust toxic syndrome among dairy farm workers – the researchers recommend longitudinal research to better assess timing of onset and long-term impacts.

The documented diminished air and water quality, in addition to other characteristics of farms like odour and flies, has contributed to decreased property values surrounding intensive livestock operations in some jurisdictions. Research conducted in the United States has found declines of up to 50% value loss of properties close to these facilities in some states (Kilpatrick, 2001). A study examining the perceptions of individuals living within 8 km of recently opened dairy farms found that 90% of respondents believed their property value had decreased. Approximately three-quarters of the sample believed the water quality had diminished. Other nuisances were reported, including odour (79%) and flies (84%) (Schmalzried and Fallon, 2007).

Emissions and Global Climate Change

Global climate change has been widely recognized as “the most serious environmental challenge humanity has to face” (FAO, 2013: i). As such, there has been significant research conducted in recent years on the potent contributors to greenhouse gas (GHG) emissions, including the dairy industry.

Before delving into the GHG emissions produced by the industry, a brief overview of assessment methods used is necessary. Historically the focus was on environmental impacts produced on-farm; however, assessments restricted to on-farm emissions only provided part of the picture. The value of life cycle assessment has becoming apparent in recent years. It is a more comprehensive and preferable method that includes more expansive processes that go into dairy production, such as the production of feed for the animals, transportation inputs and outputs, production of packaging (for an exhaustive list, see FAO 2010). The animals included in assessments of the dairy industry can also vary: some include not just the animals who are milked, but also the animals who are produced through the process of continual impregnation to ensure continued milk production, as well are replacement animals (e.g., FAO 2010).

The Food and Agriculture Organization of the United Nations (2010) conducted a life cycle assessment of the dairy sector for the year 2007.[2] Based on the analyses, they estimate that the dairy sector is responsible for 4% of the global GHGs. Of the overall livestock sector GHG emissions, cattle milk production alone accounts for one-fifth (FAO 2013).

The FAO (2010) analysis disaggregates estimates for the three main GHGs produced by the dairy industry – carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) – for both developing and developed countries. Of the GHG produced by the dairy sector, they estimate that methane accounts for 52% for developed and developing, nitrous oxide accounts for 27% (developed countries) and 38% (developing countries), and carbon dioxide for 21% in developed and 10% in developing countries.

Globally, while there have been reductions in GHG emissions per unit of production, absolute emissions levels increased approximately 18% from 2005 to 2015. During this same period there has been a 14% increase in the number of cows in dairy production and a 15% increase in production per cow. The result is that the amount of milk produced globally increased by 30% across those ten years (FAO, 2019; also see Sharma, 2020).

A number of studies have also engaged in comparative analyses between industrial scale dairy production facilities and more pasture-based methods. One key finding has been that methods that result in less GHG emissions can nonetheless increase other environmental impacts. A study conducted in the Southeast United States (Belflower, Bernard, Gattie, Hancock, Risse, & Rotz, 2012) found that GHG emissions are higher in the industrial mode of production as opposed to pasture-based, but after taking into account the amount of emissions per unit produced, the emissions output of both were similar. Their findings regarding other environmental indicators include that the pasture method had less measurable impact on erosion and phosphorus runoff; however, it did contribute to more significant nitrate leaching than the industrialized method. They also found that when taking carbon sequestration in the land into account, the carbon footprint of dairy produced via the pasture method is 12% less than the industrialized method.  

The dairy sector, like other livestock sectors, faces a real challenge in trying to reduce its emissions (while trying not to worsen its other environmental impacts) because a great deal of its emissions come from the physiological processes of the animals and therefore are inherent to producing animal-derived products. Digestion and manure in particular are responsible for a significant share of emissions in the livestock commodity chain. Acknowledging this problem, the FAO (2019) has suggested that the dairy sector work to offset its emissions. They point to three areas where these efforts can be focused: improving efficiencies, engaging in carbon capture and sequestration, and using more circular bio-economic methods. But these efforts will require expenditures that could undercut profits. Cutting its absolute GHG emissions will also be a challenge for the industry because global consumption is increasing: annual increases in global milk production averaged 2.8% between 2005 and 2015 (FAO 2019).

Despite these challenges to doing so, the industry will be under increasing pressure in the coming years to decrease their absolute emissions: “Absolute emissions reduction will become an imperative as the world moves towards carbon neutrality by 2050. While recognizing the responsibility of the dairy sector to develop in a sustainable manner, the mitigation potential of the sector is limited because, as a biological process, emissions will always be generated” (FAO, 2019: 8).

Conclusion

Dairy consumption globally is projected to double in the fifty-year period between 2000 and 2050 (FAO 2010). Due to the physiological processes involved, circumventing an absolute increase in GHG emissions is unlikely. Moreover, as discussed herein, efforts to reduce GHG emissions can come with the trade-off of exacerbating other environmental impacts. And while the FAO has recommended that the industry work to off-set their GHG emissions, there will be a price to be paid for doing so, which is likely to be unattractive to profit-motivated companies.

The warming climate may also exacerbate the negative environmental impacts of the dairy sector, as the quality of land and feed may be reduced. As one group of researchers explains, “while measures at animal level such as supplementation of lipids in the diet and decreasing dietary protein and at soil level such as nitrification inhibitors can drive perhaps 10% reductions in overall emissions, the predictions from this work suggest that these will be offset by increased animal numbers even on the poorest land for dairy production” (Sharma, Humphreys, & Holden, 2018: 631). In other words, environmental well-being and dairy production are likely to remain at odds.

“Dairy and the Environment” has been authored by Amy J. Fitzgerald, PhD, MA, BA (Hons), Senior Advisor, Associate Professor, Department of Sociology, Anthropology, and Criminology / Great Lakes Institute for Environmental Research.

Dr. Fitzgerald's research is situated at the culture/nature nexus and focuses on the perpetration of harms (criminal and otherwise) by humans against the environment and nonhuman animals. She has interrogated this broad area of inquiry vis-à-vis several topical areas, including the coexistence of animal abuse and intimate partner violence; industrialized animal agriculture; sport hunting culture; the pet food industry; the animal advocacy and environmental movements; animal cruelty laws and investigations; and environmentally-mediated human health risks.

Her work is interdisciplinary, although she draws from and contributes most specifically to the fields of green criminology, (critical) animal studies, environmental sociology, and gender studies.

Visit Amy’s website.

References:

Beirne, P. 2020. Wildlife trade and COVID-19: Towards a criminology of anthropogenic pathogen spillover. British Journal of Criminology. Available here.

Belflower, J., Bernard, J., Gattie, D., Hancock, D., Risse, L., and Rotz, C. 2012. A case study of the potential environmental impacts of different dairy production systems in Georgia. Agricultural Systems 108: 84-93.

Centner, T. J. 2006. Governmental oversight of discharges from concentrated animal feeding operations. Environmental Management, 37(6): 745-52.

Dairy Farmers of Canada. 2020. 2019-2020 Annual Report.

Eastman, C., Schenker, M., Mitchell, D., Tancredi, D., Bennett, D., and Mitloehner, F. 2013. Acute pulmonary function change associated with work on large dairies in California.  JOEM 55(1): 74-79.

Fitzgerald, A. 2015. Animals as Food: (Re)connecting Production, Processing, Consumption, and Impacts. East Lansing: Michigan State University Press.

Fitzgerald, A., Wilson, A., Bruce, J., Wurdemann-Stam, A., & Neufeld, C. (2021). Canada’s proposed prison farm program: Why it won’t work and what would work better. Evolve Our Prison Farms. Available here.

Food and Agriculture Organization of the United Nations. 2019. Climate change and the global dairy cattle sector: The role of the dairy sector in a low-carbon future. Rome.

Food and Agriculture Organization of the United Nations. 2015. Global dairy and GHG emissions: FAO Analysis 2005-2015. Rome.

Food and Agriculture Organization of the United Nations. 2013. Tackling climate change through livestock – A global assessment of emissions and mitigation opportunities. Authored by Gerber, P.J., Steinfeld, H., Henderson, B., Mottet, A., Opio, C., Dijkman, J., Falcucci, A. & Tempio, G. Rome.

Food and Agriculture Organization of the United Nations. 2010. Greenhouse gas emissions from the dairy sector: A life cycle assessment. Rome.

FoodPrint. N.d. The Foodprint of Dairy. Available here.

Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services IPBES. 2019. Summary for policymakers of the global assessment report on biodiversity and ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. S. Díaz, J. Settele, E. S. Brondízio E.S., H. T. Ngo, M. Guèze, J. Agard, A. Arneth, P. Balvanera, K. A. Brauman, S. H. M. Butchart, K. M. A. Chan, L. A. Garibaldi, K. Ichii, J. Liu, S. M. Subramanian, G. F. Midgley, P. Miloslavich, Z. Molnár, D. Obura, A. Pfaff, S. Polasky, A. Purvis, J. Razzaque, B. Reyers, R. Roy Chowdhury, Y. J. Shin, I. J. Visseren-Hamakers, K. J. Willis, and C. N. Zayas (eds.). IPBES secretariat, Bonn, Germany.

Kevany, S. January 18, 2021. ‘We need answers’: why are people living near Dutch goat farms getting sick? The Guardian. Available here.

Kilpatrick, J. 2015. Animal operations and residential property values. The Appraisal Journal, 83(1): 41-50.

Kima, N., Rotzb, C., Veltmanc, K., Chased, L., Coopere, J., Ingrahamf, P.,  Izaurraldeg, R., Jonesh, C., Gaillardi, R., Aguirre-Villegasj, H., Larson, R., Ruarkk, M., Salasf, W., Jolliet, O., Thomaa, G. 2019. Analysis of beneficial management practices to mitigate environmental impacts in dairy production systems around the Great Lakes. Agricultural Systems 176: 1-12.

Luque-Larena, J., Mougeot, F., Arroyo, B., Lambin, X. 2018. ‘Got rats?’ Global environmental costs of thirst for milk include acute biodiversity impacts linked to dairy feed production. Global Change Biology 24: 2752-2754.

Mekonnen, M. and Hoekstra, A. 2012. A global assessment of the water footprint of farm animal products. Ecosystems 15: 401-415.

Menger, L., Pezzutti, F., Tellechea, T., Stallones, L., Rosecrance, J., & Roman-Muniz, I. 2016. Perceptions of Health and Safety among Immigrant Latino/a Dairy Workers in the U.S. Frontiers in Public Health, 4(6).

Salvadori, M., Sontrop, J., Garg, A., Moist, L., Suri, R., & Clark, W. 2009. Factors that led to the Walkerton tragedy. Kidney International, 75 (Suppl 112), S33-S34S33.

Schmalzried, H. and Fallon, L. 2007. Large-scale dairy operations: Assessing concerns of neighbors about quality of life issues. Journal of Dairy Science 90: 2047-2051.

Sharma, P., Humphreys, J., Holden, N. 2018. The environmental impact of dairy production on poorly drained soils under future climate scenarios for Ireland. Journal of Environmental Management 223: 625-632.

Sharma, S. 2020. Milking the Planet: How Big Dairy is heating up the planet and hollowing rural communities. The Institute for Agriculture and Trade Policy.

Thomassen, M. and de Boer, I. 2005. Evaluation of indicators to assess the environmental impact of dairy production systems. Agriculture, Ecosystems and Environment 111: 185-199.

West, B., Liggit, P., Clemens, D. & Francoeur, S. 2011. Antibiotic Resistance, Gene Transfer, and Water Quality Patterns Observed in Waterways near CAFO Farms and Wastewater Treatment Facilities. Water Air and Soil Pollution, 217: 473-89.

1. The United States is the only North American country they examine.

2. They report a fairly large margin of error (26% ) due to data-related challenges. The literature is replete with calls for improved efforts at data collection and compilation.